Effects of dietary sodium selenite and organic selenium sources on immune and inflammatory responses and selenium deposition in growing pigs

Abstract

The study was conducted to compare effects of different dietary Se sources (sodium selenite [NaSe], Se-enriched yeast [Se yeast] or L-selenomethionine [SeMet]) and one Se-deficient control diet on the expression of selected genes, hematological and clinical biochemical parameters, and muscle morphology in two parallel trials with finisher pigs. Se concentrations in blood plasma and tissues were also monitored. From the pigs in one of the parallel groups, muscle samples obtained from Musculus longissimus dorsi (LD) before and during the trial were examined. The pigs in the other parallel group were challenged once with lipopolysaccharide (LPS) intravenously. Transcriptional analyses of LD showed that selenogenes SelenoW and H were higher expressed in pigs fed Se-supplemented diets compared with control. Furthermore, the expression of interferon gamma and cyclooxygenase 2 was lower in the Se-supplemented pigs versus control. In whole blood samples prior to LPS, SelenoN, SelenoS and thioredoxin reductase 1 were higher expressed in pigs fed NaSe supplemented feed compared with the other groups, possibly indicating a higher level of oxidative stress. After LPS exposure glutathione peroxidase 1 and SelenoN were more reduced in pigs fed NaSe compared with pigs fed organic Se. Products of most above-mentioned genes are intertwined with the oxidant-antioxidant system. No significant effects of Se-source were found on hematologic parameters or microscopic anatomy. The Se-concentrations in various skeletal muscles and heart muscle were significantly different between the groups, with highest concentrations in pigs fed SeMet, followed by those fed Se yeast, NaSe, and control diet. Consistent with previous reports our results indicate that dietary Se at adequate levels can support the body's antioxidant system. Our results indicate that muscle fibers of pigs fed organic Se are less vulnerable to oxidative stress compared with the other groups.

Myopathy as a Destabilizing Factor of Meat Quality Formation

“…Up to now, the results of these studies were not considered successful, despite the fact that several substances can inhibit tissue enzymes (for example, citrates and acetates -phosphofructokinase) [44]. To prevent the emergence and development of nutritional myopathies, investigations have been continued in the field of studying an effect of different doses of selenium and vitamin E with regard to sources of these substances, dura-tion of feeding period, feed composition and other factors [1,12,40,43,45,46].…”

“…On the contrary, deficiency of vitamin E in combination with lowered selenium status, can lead to nutritional myopathy in different species. In this connection, selenium was recognized as an important nutrient and was involved in explanation of causes of nutritional myopathy as far back as the end of the 1950s [3,40].…”

“…Nevertheless, lesions ranged from microscopic to pronounced macroscopic can be observed in muscles in experimental investigations of nutritional myopathy in pigs. In the severe form of the disease microscopic lesions of porcine muscles consist in multifocal polyphasic necrosis [3,40].…”

“…Mild changes were defined as the presence of individual, separated muscle fibers with increased volume and loss of striation or a very low number of degenerating muscle fibers, sometimes with mild infiltration of macrophages. Moderate changes were defined as multifocal degenerating or necrotic muscle fibers with or without infiltration of macrophages, while severe changes were defined as multifocal, relatively widespread degenerating or necrotic muscle fibers with or without infiltration of macrophages [40].…”

“…Recently, it has been found that levels of selenium and vitamin E intake that earlier were considered sufficient, do not exclude the development of nutritional myopathy. In this connection, at present, the question of correspondence of existing strategies of feeding highly productive pigs in the context of assurance of their health and, consequently, quality of produced pork has been raised [40].…”